Electrical measuring instrument



C. T. ALLCUTT.

ELECTRICAL MEASURING INSTRUMENT.

APPLICATION FILED MAI-(1,1917- 1,385,979, v PatentdAug. 2,1921.

I WITNESSES: INVENTOR 1 he5fr 7.'/7//cof[ BY a; 'ATTORNEY be produced between the CHESTER T. ALLCUTT, O35 WILKINSBURG,

HOUSE ELECTRIC 8G MANUFACTURING COMPANY,

VAN IA.

PENNSYLVANIA, ASSIGNOR T0 W'ESTING- A CORPORATION OF PEN N SYL- ELECTRICAL MEASURING INSTRUMENT.

Specification of Letters Patent.

Patented Aug. 2, 1921.

Application filed March 2, 1917. Serial No. 151,989.

To all whom it may concern:

Be it known that I, CHESTER T. ALLoU'rr, a citizen of the United States, and a resident of lVilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Electrical Measuring Instruments, of which the following is a specification.

invention relates to electrical measuring instruments and particularly to means for, and methods of, so producing sym metrical rotating electrostatic fields that the phase-relations in a single-phase circuit may be readily determined.

One object of my invention is to provide a measuring instrument of the above indicated character that shall accurately indicate the phase-relation or power-factor of a single-phase circuit.

Another object of my invention is to provide means whereby the current traversing a single-phase circuit may be so applied to a plurality of conducting members that a symmetrical rotating electrostatic field may conducting members.

In practising my invention, I provide two movable conducting members that are operatively connected to the respective conductors of the circuit the phase-relation of which is to be determined, four stationary conducting members that are arranged around the movable conducting members and a bridge that is connected in series with the circuit and has equal-capacity reactance and resistance arms. The terminals of the bridge are connected to the respective stationary conducting members for the purpose of producing a symmetrical rotating electrostatic field therebetween. A pointer may be attached to the movable conducting members to cooperate with a scale to indicate the power-factor of the circuit. That is, the movable conducting members will turn to predetermined positions in accordance with the phase-angular relation between the cur-- rent and the voltage of the circuit.

The single figure of the accompanying drawing is a diagrammatic view of an electrostatic power-factor meter embodying my invention.

The electrostatic power-factor meter 1 comprises, in general, two movable conducting members 2 and .3, a pointer 41, a scale 5,

alternating-curl'fil four stationary conducting members 6, 7, 8 and 9 and aphasesplitting bridge 10.

The conducting members 2 and 3 are substantially spherical in shape and are mounted on the respective ends of an insulating member 11. he member 11 is mounted on a shaft 12 upon which the pointer 4a is also mounted, and the members 2 and 3 are connected to the respective conductors 13 and 14: of the circuit 15 the power-factor of which is to be determined.

The phase-splitting bridge 10 comprises four arms 16, 17, 18 and 19,-the arms 16 and 19 of which have substantially equal resistances of suiiiciently large value toobtain a relatively high voltage drop when full-load current traverses the circuit 15. The arms 17 and 18 comprise condensers having capacity reactances substantially equal to the resistances of the arms 16 and 19. By such an arrangementof resistors and condensers, the current traversing the circuit 15 may be so split that four different out-of-phase potentials may be obtained at the respective terminals of the bridge. That is, the conducter 8 is connected to the terminal 20 of the bridge, the conductor 7 is connected to the terminal 21, the conductor 6 connected to the terminal22, and the conductor 9 is connected to the terminal 23 ot' the bridge, to thus cause a symmetrical rotating electrostatic field to be produced between the conductors 6, 7, 8 and 9.

It will be readily understood that ,the movable members 2 and 3 are responsive to the potential, and that the members 6, 7, 8 and 9 are responsive to the current, of the circuit 15. It will also be understood that the members 6, 7, 8 and 9 may be movable and the members 2 and 3 stationary, if desired, it being merely necessary that there shall be relative movement between the two sets of members.

If the members 2 and 3 are placed at random with respect to the members 6, 7, 8 and 9, a torque will be exerted between the stationary and movable members. However, since the movable members 2 and 3 are free to move without restraint, they will turn under the influence of the torque that is produced until they assume a position where the torque becomes zero. If, under these conditions, the currents of the circuit are in phase value or the power-factor.

, ular arrangement .members 2 and 3 to with the potential oi the circuit, this position of the pointer 4% will indicate unity power-factor on the scale 5. If-the currents in the circuit 15 shift in phase relatively to the electromotive forces, the rotating electrostatic field between the stationary members 6, 7, 8 and 9 will shift correspondingly in time phase, thereby disturbing the balance of the torque existing between the movable and the stationary conducting members of the instrument to cause the movable assume a new position to the new The varying values of power-factor are thus indicated by the positions assumed by the movable pointer 4- in cooperation with the scale 5. I do not limit my invention to the particof bridge shown nor to the particular structure of the power-factor meter, as many modifications may be'made therein without departing from the spirit and scope of the invention as the appended claims.

I claim as my. invention of equilibrium corresponding 1. Ina single-phase electric circuit, the combination with four. conducting members, of phase-splittingbridge connected mseries with the circuit, and means for so connecting the said conducting members to i the bridge that a symmetrical rotating elec trostatic field is produced between the said conducting members.

2. In a single-phase electric circuit, the combination with a plurality of conducting members, of a phase-splitting bridge convnected in series with the circuit, and means for connecting the said conducting members to the respective terminals ofv the bridge to produce a symmetrical rotating electromembers. it s 3. A power-factor meter for a single- 511M310, field between the said conducting phase circuit comprising two movable conducting members connected to the res )ect-ive conductors. of the ,C11C111t, four stationary conducting members, and a set forth in I tween the stationary nected to the circu'i phase-splitting two movable conducting members connected to the respective conductors of the circuit, and four stationary conducting members, of a bridge comprising equal-capacity reactance and resistance arms connected in series with the circuit and to the stationary conducting members.

5. In a phase-indicating instrument for a single-phase circuit, the combination with two movable conducting members connected to the respective conductors of the circuit, and four stationary conducting members, 01" a phase-splitting bridge connected to the circuit, and means for so connecting the stationary conducting members to the terminals of the bridge that a rotating symmetrical electrostatic field is produced beconducting members.

6. In a ahase-indicatin instrument for a singlephase circuit, the combination with cooperating relatively movable conducting members, of a phase-splitting bridge cont, and means torso c0nnecting the said conducting members to the terminals of the bridge and the circuit that they will assume definite positions with respect to each other in accordance with the phase-relationbetween the current and voltage of the circuit. i o p 7, In a single-phase circuit, thecombination with tour stationary symmetricallydisposed conducting members, a movable conducting member, a phase-splitting bridge connected in" series with the circuit, and means for connecting the stationary conducting members to the respective terminals of the bridge and the movable'conducting member to the single-phase circuit. I

in testimony subscribed my name whereof, I have hereunto. 

